[PATCH net-next 12/15] nfp: bpf: calculate code store ECC

[Jakub Kicinski]

In the initial PoC firmware I simply disabled ECC on the instruction
store.  Do the ECC calculation for generated instructions in the driver.

Signed-off-by: Jakub Kicinski <jakub.kicin...@netronome.com>
Reviewed-by: Simon Horman <simon.hor...@netronome.com>
---
 drivers/net/ethernet/netronome/nfp/bpf/jit.c | 20 +++++++++++++++
 drivers/net/ethernet/netronome/nfp/nfp_asm.c | 37 ++++++++++++++++++++++++++++
 drivers/net/ethernet/netronome/nfp/nfp_asm.h |  3 +++
 3 files changed, 60 insertions(+)

diff --git a/drivers/net/ethernet/netronome/nfp/bpf/jit.c 
b/drivers/net/ethernet/netronome/nfp/bpf/jit.c
index 9b6c98ccebfe..f4aedc89bfc8 100644
--- a/drivers/net/ethernet/netronome/nfp/bpf/jit.c
+++ b/drivers/net/ethernet/netronome/nfp/bpf/jit.c
@@ -1715,6 +1715,23 @@ static int nfp_bpf_optimize(struct nfp_prog *nfp_prog)
        return 0;
 }
 
+static int nfp_bpf_ustore_calc(struct nfp_prog *nfp_prog)
+{
+       int i;
+
+       for (i = 0; i < nfp_prog->prog_len; i++) {
+               int err;
+
+               err = nfp_ustore_check_valid_no_ecc(nfp_prog->prog[i]);
+               if (err)
+                       return err;
+
+               nfp_prog->prog[i] = nfp_ustore_calc_ecc_insn(nfp_prog->prog[i]);
+       }
+
+       return 0;
+}
+
 /**
  * nfp_bpf_jit() - translate BPF code into NFP assembly
  * @filter:    kernel BPF filter struct
@@ -1766,8 +1783,11 @@ nfp_bpf_jit(struct bpf_prog *filter, void *prog_mem,
                pr_err("Translation failed with error %d (translated: %u)\n",
                       ret, nfp_prog->n_translated);
                ret = -EINVAL;
+               goto out;
        }
 
+       ret = nfp_bpf_ustore_calc(nfp_prog);
+
        res->n_instr = nfp_prog->prog_len;
        res->dense_mode = false;
 out:
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_asm.c 
b/drivers/net/ethernet/netronome/nfp/nfp_asm.c
index 1decc638ea6f..de76e7444fc2 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_asm.c
+++ b/drivers/net/ethernet/netronome/nfp/nfp_asm.c
@@ -215,3 +215,40 @@ int swreg_to_restricted(swreg dst, swreg lreg, swreg rreg,
 
        return 0;
 }
+
+#define NFP_USTORE_ECC_POLY_WORDS              7
+#define NFP_USTORE_OP_BITS                     45
+
+static const u64 nfp_ustore_ecc_polynomials[NFP_USTORE_ECC_POLY_WORDS] = {
+       0x0ff800007fffULL,
+       0x11f801ff801fULL,
+       0x1e387e0781e1ULL,
+       0x17cb8e388e22ULL,
+       0x1af5b2c93244ULL,
+       0x1f56d5525488ULL,
+       0x0daf69a46910ULL,
+};
+
+static bool parity(u64 value)
+{
+       return hweight64(value) & 1;
+}
+
+int nfp_ustore_check_valid_no_ecc(u64 insn)
+{
+       if (insn & ~GENMASK_ULL(NFP_USTORE_OP_BITS, 0))
+               return -EINVAL;
+
+       return 0;
+}
+
+u64 nfp_ustore_calc_ecc_insn(u64 insn)
+{
+       u8 ecc = 0;
+       int i;
+
+       for (i = 0; i < NFP_USTORE_ECC_POLY_WORDS; i++)
+               ecc |= parity(nfp_ustore_ecc_polynomials[i] & insn) << i;
+
+       return insn | (u64)ecc << NFP_USTORE_OP_BITS;
+}
diff --git a/drivers/net/ethernet/netronome/nfp/nfp_asm.h 
b/drivers/net/ethernet/netronome/nfp/nfp_asm.h
index 40a51a45afd7..d95087e5fb73 100644
--- a/drivers/net/ethernet/netronome/nfp/nfp_asm.h
+++ b/drivers/net/ethernet/netronome/nfp/nfp_asm.h
@@ -362,4 +362,7 @@ int swreg_to_unrestricted(swreg dst, swreg lreg, swreg rreg,
 int swreg_to_restricted(swreg dst, swreg lreg, swreg rreg,
                        struct nfp_insn_re_regs *reg, bool has_imm8);
 
+int nfp_ustore_check_valid_no_ecc(u64 insn);
+u64 nfp_ustore_calc_ecc_insn(u64 insn);
+
 #endif
-- 
2.14.1